1. Field of the Invention
The present invention relates to shock absorbing components and to methods of manufacturing shock absorbing components. More particularly, the invention relates to flexible shock absorbing components used for a variety of surfaces, including cushioning for medical purposes, packaging material, athletic protective padding, footwear, exercise equipment padding, seating, industrial safety padding, exercise mats and resilient hard surface covering.
2. Description of Related Art
Efforts to improve shock absorbing materials have centered on decreasing weight and improving cushioning, flexibility, and stability. In particular, shock absorbing materials for footwear and athletic equipment have focused on improved shock dispersion capabilities. Additionally, the modern design of shock absorbing materials takes into account the specific requirements of padding and cushioning for particular activities. Although the functional characteristics of shock absorbing materials are of primary importance, other factors such as cost and appearance must be taken into account for full consumer satisfaction.
Typically, shock absorbing materials for footwear and athletic equipment use plastics expanded into foams which are then shaped in a number of ways to accommodate the application requirements. In certain applications, an outer layer of rubber or other material is added, requiring layering both surfaces with cement where they are to be joined, then activating the treated surfaces, usually with heat. Disadvantages of cementing or adhering sufaces together include cost, weight and appearance.
Shock absorbing components also have been constructed of a shell of a thermoplastic elastomer designed to encapsulate and protect low density synthetic foams such as polyether, polyurethane or polyester polyurethane. Other shock absorbing components typically include an air cushion or bladder which may be filled or inflated with a gas or fluid to a desired pressure. Disadvantages of these types of components include cost and difficulty of sealing the component.